1. Field of the Invention
The invention relates to an improved light weight vibration-damping sheet which mainly comprises an asphalt component and a hollow filler component and is manufactured by melting asphalt, mixing hollow fillers therewith and rolling the mixture into a form of sheet.
2. Prior Art
It is well known to employ a vibration-damping sheet in vehicles, particularly in automobiles, in order to reduce vibration caused by an engine. Usually, the sheets are firmly fixed by fusion or placed on the steel panel of the car floor, of the door, or of the trunk.
The applicants have already disclosed a heat fusible light weight vibration-damping sheet composition, which mainly comprises an asphalt component and a hollow silicate filler component in order to reduce the weight of said composition, in the specification of Japanese laid open 77-39723 Kokai 52-39723). In this prior art light weight vibration-damping sheet composition, the objective of the weight reduction is accomplished by the use of a hollow silicate filler whereas the workability of said composition into a sheet form is not satisfactory.
In general, for the purpose of reducing the weight of the automobile, a thinner vibration-damping sheet is often applied to the automobile but, on the other hand, the vibration-damping effect of the thinner sheet decreases and the level of the vibration is not tolerable to the drivers or the passengers.
By use of the above mentioned light weight vibration-damping sheet composition having a hollow filler component, weight reduction purpose is achieved but the sheet forming workability of said composition is not sufficient because it is difficult to disperse hollow silicate filler uniformly in asphalt.
The objective of this invention is to solve the above mentioned problem, that is, to disperse hollow silicate filler uniformly in asphalt.